Hi Mario,
I had similar issues with SPI on my own design. It worked sometimes, bot not others. I tried all the combinations for SPI config both for DW1000 and host (I’m using Microchip PIC16F and 18F controllers) bit nothing helped. Except one thing…
I put a small 330pF ceramic capacitor to DW1000 SPIMOSI pin (pin 39 on DW1000 IC) and GND, close to the chip. It not only works for the IC itself, but same applied for me to DWM1000 module.
I’m unsure about the explanation but seems that PIC controllers have no match for impedance on SPI. Probably caused by the peripheral selection module inside them (which allows to configure in and outputs as a matrix).
I’m unsure if this would help you as I haven’t used other controllers with DW1000 yet. Also, I’m using SPI on 8MHz, but the issue was there even on slower frequencies (which even contradict my impedance theory, but in fact it’s working).
I hope you can fix your issue soon, I know how annoying it is, I spent reasonable time to fix my design.
Good luck.
Thanks
Dez